In UMTS (Universal Mobile Telecommunications System), there is a technology known as MOCN (Multi-Operator Core Network) for the sharing of wireless access networks by the core networks (CNs) of a plurality of communication operators (see Patent Documents 1 and 2).
In MOCN, when a femto-base station (HNB: Home NodeB) is shared by a plurality of communication operators, the HNB is connected with a plurality of CNs by way of an HNB-GW (HNB-Gateway). When a call is originated from a user terminal, the HNB-GW must transfer a control message from the user terminal to the appropriate CN.
At the time of starting up an HNB, the HNB must be connected to a plurality of CNs by way of an HNB-GW as described above. For this purpose, the plurality of CNs that are to connect with the HNB must be reported to the HNB-GW at the start-up time of the HNB.